How Safe Is It to Clean a Tile Roof with Bleach?

Roof cleaning is often performed by contractors using sodium hypochlorite (bleach). Although some industry groups recommend a diluted bleach solution, many homeowners are questioning whether it is safe for tile roofs. Let’s explore the risks, alternatives, and best practices.

Is Bleach Safe for Tile Roofs?

Despite being widely used, bleach is not recommended for tile roof cleaning. Chlorine bleach is corrosive, accelerates roof tile damage, and its runoff harms vegetation. It only makes algae stains translucent, meaning the stains reappear within a year, forcing repeated cleanings.

Bleach also corrodes roof fixtures like flashing, valleys, and underlayments. Contractors using “soft wash” often mix bleach with phosphates and detergents, which are harmful to the environment and vegetation.

Safer Chemicals to Clean Roof Tiles

• Krud Kutter Multi-Purpose House Wash – Biodegradable, non-toxic, and safe for vegetation.
• Defy Roof Cleaner – Eco-friendly, made with detergents, sodium metasilicate, soda ash, and sand. Harmless to vegetation when diluted.
• Sodium Hydroxide-based cleaners – Effective degreasers that are environmentally safer alternatives.

Whichever product you choose, always check your roof manufacturer’s guidelines and use the mildest cleaning solution possible.

How Often Should a Tile Roof Be Cleaned?

Cleaning frequency depends on your roof’s condition, age, climate, and surrounding trees. On average:

• Concrete tile roofs: Every 2–3 years, as they retain moisture longer and develop algae faster.
• New tile roofs: First cleaning typically after 5 years.

Regular cleaning improves roof lifespan, energy efficiency, and appearance.

Best Practices for Cleaning a Tile Roof

1. Take safety precautions – Wear non-slip shoes, gloves, glasses, and use a safety harness if needed.
2. Use low-pressure washing – High pressure can erode tile finishes.
3. Apply eco-friendly cleaners – Let the solution soak and reapply if algae and moss are stubborn.
4. Clear gutters – Prevent clogs and water damage during heavy rain.
5. Inspect for damage – After cleaning, check for cracked tiles or leaks.

Summary,

While bleach is often promoted for roof cleaning, it poses risks to tile roofs, fixtures, and the environment. Instead, use eco-friendly, non-bleach cleaning solutions combined with low-pressure washing. This ensures your tile roof lasts longer, maintains its beauty, and minimizes harm to your surroundings.